Spectro is not available for Mac but there are a few alternatives that runs on macOS with similar functionality. The best Mac alternative is Ocenaudio, which is free. If that doesn't suit you, our users have ranked more than 10 alternatives to Spectro and four of them are available for Mac so hopefully you can find a suitable replacement. Other interesting Mac alternatives to Spectro are Lossless Audio Checker (Free), Smaart (Paid) and sndpeek (Free, Open Source).
Ocenaudio is a cross-platform, easy to use, fast and functional audio editor. It is the ideal software for people who need to edit and analyze audio files without complications. ocenaudio also has powerful features that will please more advanced users.
sndpeek is just what it sounds (and looks) like: - real-time 3D animated display/playback - can use mic-input or wav/aiff/snd/raw/mat file (with playback) - time-domain waveform - FFT magnitude spectrum - 3D waterfall plot